Delay arming mechanism

ABSTRACT

A delay arming mechanism having an outer housing and an inner housing rotatably mounted within the outer housing. A firing mechanism is also located within the inner housing and a plurality of lockweights prevent the movement of the firing mechanism. Upon spinning of the outer housing, the inner housing initially remains stationary due to its inertia. Eventually due to friction the inner housing also begins to spin. At a predetermined RPM the lockweights within the inner housing move out of engagement with the firing mechanism and allows for its movement into the actuating position. It is the time necessary for the inner housing to reach the speed of the outer housing which constitutes the delay time of this invention.

United States Patent 1 Nov. 28, 1972 Semenza [54] DELAY ARNIING NIECHANISM [72] Inventor: Eugene Semenza, Buffalo, Minn.

[73] Assignee: The United States of America as represented by the Secretary of the United States Air Force [22] Filed: May 20, 1970 [21] Appl. No.: 39,946

[52] US. Cl ..102/70 S, 102/79 [51] Int. Cl. ..F42c 15/22 [58] Field of Search ..102/70, 79, 76, 64, 78

[56] References Cited UNITED STATES PATENTS 3,136,253 6/1964 Kulesza et a1 102/79 3,516,359 6/1970 Weber et a1. ..102/79 3,356,028 12/1967 Heinemann ..102/79 2,779,286 1/1957 Marshall ..102/79 X Primary Examiner-Samuel W. Engle Attomey--Harry A. Herbert, Jr. and Jacob N. Erlich ABSTRACT A delay arming mechanism having an outer housing and an inner housing rotatably mounted within the outer housing. A firing mechanism is also located within the inner housing and a plurality of lockweights prevent the movement of the firing mechanism. Upon spinning of the outer housing, the inner housing initially remains stationary due to its inertia. Eventually due to friction the inner housing also begins to spin. At a predetermined RPM the lockweights within the inner housing move out of engagement with the firing mechanism and allows for its movement into the actuating position. It is the time necessary for the inner housing to reach the speed of the outer housing which constitutes the delay time of this invention.

6Clains,2DrawingFigures DELAY ARMING MECHANISM BACKGROUND OF THE INVENTION This invention relates generally to fuzes, and more particularly to a delay arming type of mechanism utilized with a spin-toarm fuze.

In many types of devices, and more specifically in bombs or mines which are to be activated, upon spinning it is desirable for the arming mechanism to activate the device after a short delayplt is important that these arming mechanisms do not function until after the bomb or device is released. In this manner the bomb or device can be delivered outside the radius of danger of the delivering means. Furthermore, this provides some degree of safety in the case of falling bombs which strike each other, in the case where the'bombs are released while the plane is on the ground or at a low altitude, and in the case where the bomb has been released inadvertently. The percentage of failures of the arming mechanism should also be at a minimum.

If, for example, in a dispenser system a group of mines was safety-jettisoned on an aircraft carrier, the dispenser would then hit the surface of the aircraft carrier and spew the mines down the runway. Some ofthe mines rolling would spin up due to their forward inertia and could exceed the arming speed. It is necessary to have an arming mechanism which does not reach the arming speed until the spinning action has been sustained for a given period of time. In another instance, if a cannister full of mines opened immediately upon jettison from an aircraft and the mine armed itself immediately upon reaching the spinning velocity, the distance from the aircraft may be so close as to cause damage during the firing of the mine.

l-leretofore, complex mechanisms wereneeded in the spin-to-arrn arming mechanism in order to prevent the unacceptable arming of a mine or bomb or other device which is to be activated upon spinning of the device to a proper speed. The complexity of these arming mechanisms made for an increased number of failures during operation. Furthermore, the increased complexity greatly increased the cost of manufacture.

SUMMARY OF THE INVENTION The instant invention sets forth an arming mechanism which overcomes the problems set forth hereinabove.

The purpose of the instant invention is to set forth an arming mechanism which is capable of delaying the arming of a spin-to-arm device. The main fuze case of the bomb, mine or device is connected directly to the arming mechanism of this invention. Normally when the main fuze case spins up, a lockweight within the arming mechanism also spins with the device. However, in this invention, the lockweight housing inertia will tend to cause it to remain stationary as the arming mechanism base starts to spin, due to the housing being separated from the base by bearings. The bearings, since they are not friction-free, cause the lockweight housing to eventually come up to speed with the base. The time necessary for this to happen is the delay time associated with the instant invention. The arming speed is adjusted in this invention by varying the weight of the lockweights within the lockweight housing and the dimension of the springs which hold the lockweights in position. In other words, if the arming speed is 3,000 RPM, when the lockweight housing reaches 3,000 RPM, the lockweights will move radially outward against the lockweight springs which will then allow for the release of a firing pin. The firing pin of this invention is designed to initiate a firing primer. This will then activate the device associated with the arming mechanism of the instant invention.

It is an object of this invention to provide an arming mechanism which is to be utilized in delaying the arming of a spin-to-arm device.

It is another object of this invention to provide an arming mechanism which is of simple construction and therefore extremely accurate in operation.

It is still another object of this invention to provide an arming mechanism which isof extremely durable construction.

It is a further object of this invention to provide an arming mechanism which is economical to produce and which utilizes conventional currently available materials that lend themselves to standard mass producing manufacturing techniques.

For a better understanding of this invention together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE DRAWING FIG. 1 of the drawing is a top view of the arming mechanism of this invention with the cover removed and shown partially in cross-section; and

FIG. 2 of the drawing is a cross-sectional view of the arming mechanism of this invention taken along line 22 of FIG. 1.

DESCRIPTION OF APREFERRED EMBODIMENT Reference is now made to FIG. '1 of the drawing which discloses a top view of the arming mechanism 10 of this invention. In FIG. 1, the cover 12, shown in FIG. 2, is removed so that the interior of the arming mechanism 10 of this invention can be more clearly seen.

Referring now to FIGS. 1 and 2 of the drawing, the anning mechanism 10 is made of a base portion 14 and a cover 12 which enclose a lockweight housing 16. The cover 12 is fixedly secured to the base portion 14 by any suitable securing means and has an aperture 15 in the center thereof. The lockweight housing 16 is rotatably mounted within the arming mechanism base portion 14 and cover 12 by a plurality of conventional bearing members, such as ball bearings 18. The ball bearings 18 are located within cutout portion 19 of base 14 so as to engage outstanding element 21 of lockweight housing 16. Other ball bearings 18 are located within cutout portion 23 of housing 16 and engage the cover 12. These ball bearings 18 allow for the almost friction-free rotation of lockweight housing 16 within the base 14.

A plurality of lockweights 20 are located within the lockweight housing 16 and are held in position against a firing mechanism 22 by a plurality of biasing members such as lockweight springs 24. The springs 24 are held in position at one end thereof by the outer rim 26 of the lockweight housing 16, and at the other end thereof tit within a suitable notch 28 within the lockweights 20. Each of the lockweights 20 further have thereon an outstanding element 30 which engages an outstanding element 32 on the firing mechanism 22. The firing mechanism 22 has located in an indented center portion 25 any suitable biasing means such as spring 34 which is utilized to force the firing mechanism 22 into the operative position and extending through aperture when the lockweights are removed from the blocking position against elements 32 as shown in the drawing. In the position as shown in the drawing the firing mechanism 22 is in the retracted or inoperative position and will remain in this position as long as the lockweight springs 24 force the lockweight 20 against the outstanding element 32 of the firing mechanism 22.

The main fuze case (not shown) of a bomb, mine or any other similar spin-to-arrn device is connected. by any suitable securing means directly to the arming mechanism base 14 in any conventional manner, with the firing pin 36 of firing mechanism 22 so positioned as to engage the firing primer or detonating means of that device. The lockweights 20 of the arming mechanism 10 of this invention may be made of any desired weight so as to move radially outward against the force of lockweight springs 24 when the lockweight housing 16 has spun to a predetermined speed. When the rotation of the lockweight housing 16 is so great as to force the lockweights 20 against the springs 24 and out of engagement with the outstanding element 32 on the firing mechanism 22, the firing mechanism spring 34 will force the firing mechanism 22 and its associated firing pin 36 to an outward position (not shown) completely through aperture 15 and into engagement with the firing primer on a bomb, mine or the like. It is the combination of the weight and size of the lockweights 20, the tension of the springs 24 and the amount of friction between ball bearings 18 and the lockweight housing 16 which determines at which speed the arming mechanism 10 of this invention will activate the device attached thereto.

MODE OF OPERATION In operation the main fuze case of a bomb or the like is connected directly to the arming mechanism base 14. Upon release of this device and the spinning thereof, the arming mechanism base 14 also spins. The lockweight housing 16, however, due to its inertia will initially remain stationary. The ball bearings 18, not being completely friction-free, will cause the lockweight housing 16 to finally come up to the speed with the base 14. The time interval necessary for the lockweight housing 16 to come up to speed with the base portion 14 is considered the time delay of this invention. By varying the weight of the lockweights 20 and the dimensions of the lockweight springs 24, the time at which the lockweights 20 will move radially outward against the lockweight springs 24 can be predetermined. Once the lockweights 20 move out of engagement with the firing mechanism 22, the spring 34 will force the firing mechanism 22 and the firing pin 36 completely through aperture 15 in cover 12 and into the operative or detonating position. The arming mechanism 10 of the instant invention can be utilized in any spin-to-arm device in which .a delay period is re uired before actuation thereof.

though the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments within the spirit and scope of the appended claims.

I claim:

1. A delay arming mechanism comprising an outer housing, said outer housing having a base portion and a cover with an aperture therein, an inner housing, bearing means located between said inner housing and said outer housing for rotatably supporting said inner housing, a firing mechanism having a firing pin thereon moveably mounted within said inner housing, means for moving said firing mechanism, at least one lockweight mounted within said inner housing and means located in said inner housing for biasing said lockweight into a first position against said firing mechanism thereby restraining movement of said firing mechanism, whereby spinning of said outer housing causes a delayed movement of said inner housing and subsequent movement of said lockweight into a second position against said biasing means and thereby out of contact with said firing mechanism allowing said firing pin to pass completely through said aperture.

2. A delay arming mechanism as defined in claim 1 wherein said bearing means are ball bearings.

3. A delay arming mechanism as defined in claim 2 wherein said lockweight has an outstanding element thereon for engaging said firing mechanism.

4. A delay arming mechanism as defined in claim 3 further comprising a plurality of lockweights and a plurality of means for biasing said lockweights against said firing mechanism.

5. A delay arming mechanism as defined in claim 4 wherein said means for biasing said lockweights is a spring.

6. A delay arming mechanism as defined in claim 5 wherein said means for moving said firing mechanism is a spring. 

1. A delay arming mechanism comprising an outer housing, said outer housing having a base portion and a cover with an aperture therein, an inner housing, bearing means located between said inner housing and said outer housing for rotatably supporting said inner housing, a firing mechanism having a firing pin thereon moveably mounted within said inner housing, means for moving said firing mechanism, at least one lockweight mounted within said inner housing and means located in said inner housing for biasing said lockweight into a first position against said firing mechanism thereby restraining movement of said firing mechanism, whereby spinning of said outer housing causes a delayed movement of said inner housing and subsequent movement of said lockweight into a second position against said biasing means and thereby out of contact with said firing mechanism allowing said firing pin to pass completely through said aperture.
 2. A delay arming mechanism as defined in claim 1 wherein said bearing means are ball bearings.
 3. A delay arming mechanism as defined in claim 2 wherein said lockweight has an outstanding element thereon for engaging said firing mechanism.
 4. A delay arming mechanism as defined in claim 3 further comprising a plurality of lockweights and a plurality of means for biasing said lockweights against said firing mechanism.
 5. A delay arming mechanism as defined in claim 4 wherein said means for biasing said lockweights is a spring.
 6. A delay arming mechanism as defined in claim 5 wherein said means for moving said firing mechanism is a spring. 